In recent years, wheeled luggage cases have been popularly used by travelers in various forms of transportation, specifically at airports. In designing a wheeled luggage case, a number of design criteria for the case must be satisfied. For instance, the rigidity of the structure of the case, the reliability of the wheels for extended use, and a convenient pull-handle that can be securely locked when stowed. A rigid construction of the luggage case allows for extended use in rough service environments, i.e., when the case is wheeled in the streets, in and out of buildings with stairs, and in and out of carriers such as airplanes or trains. A reliable wheel means is necessary so that the luggage can be pulled on a relatively smooth pavement with ease for a long service life. A reliable pull-handle system should be provided for convenient operation by users such that the handle may be easily stowed away when not in use.
The design of a reliable and convenient to use pull-handle system is particularly important in the design of a wheeled luggage. When the design is inadequate, the pull-handle system along with its locking means can easily fail and cause serious problems. For instance, when a wheeled luggage is laid down on a flat surface or being positioned in an upside-down manner, the locking means for the pull-handle system must function properly to prevent any accidental extension of the handle due to gravity. Any such accidental extension of the handle may cause serious damage to the luggage when it is transported on an automated conveyor belt used at airports. The design of a reliable and convenient to use locking mechanism for a pull-handle system is therefore an important aspect of the design of a wheeled luggage.
Efforts have been made by others to improve the pull-handle system for a wheeled luggage case. For instance, U.S. Pat. No. 5,526,908 discloses a retractable handle assembly which can be extended and folded without exerting a large force on the assembly. The assembly includes a hollow bracket mounted on a top plate of one of the half bodies of the case, a pair of lug portions each formed on one of the distal end portions of the bracket and each having a cavity inside, a pair of outer tubes each securely mounted between the lug portion and a bottom plate of the half body and each having a second cavity laterally defined therein for aligning with the first cavity, the pair of inner tubes each is slidably mounted on one of the outer tubes and each has a third cavity laterally defined therein for aligning with the second cavity, and a substantially U-shaped handle portion mounted on the bracket which has two free end portions each engaging the upper end of a corresponding inner tube. The assembly further includes a pressing member mounted in the hallow bracket including a knob extending from an opening of the bracket, and a biasing member mounted under the pressing member which includes a pair of stops each extending through the first cavity, the second cavity and the third cavity.
U.S. Pat. No. 5,499,426 discloses a handle device which includes a pair of storage tubes for mounting on the back of a wheeled suitcase, a seat frame, a handle member and a locking mechanism. The locking mechanism is provided in the receiving space of the seat frame which includes two projecting members and a biasing unit between the projecting members for biasing the members toward the storage tubes and for locking the handle member relative to the storage tubes when the two engaging holes are in alignment. The locking mechanism further includes a retracting unit for retracting the projecting members to release the handle member from the storage tubes.
U.S. Pat. No. 5,431,428 further discloses a carrying case which is equipped with a collapsible handle assembly stored inside the case. The handle assembly can be operated by a push button which allows the handle to collapse within the case, a lock mechanism for holding a first handle portion in an extended position relative to the second handle portion. The lock means includes a selectably releaseable handle-locking protrusion on one of the first and second handle portions which is movable in opposing directions and away from the other of the first and second handle portions into and out of engagement therewith.
U.S. Pat. No. 5,502,876 discloses a pull-handle of a luggage trunk which includes a pair of driving rods each having a wedge member disposed at the bottom end of the trunk and is in abutment with a spring biased locking seat which has an oblique cam surface. Each of the driving rod is housed in a hollow tube while the locking seat is in selective engagement with one of a plurality of spaced retaining slots disposed in a movable sleeve which accommodates each hollow tube.
Another locking mechanism that has been used in the industry is shown in FIGS. 1, 2 and 3. The locking mechanism 10 for mounting into an inner tube 12 of a wheeled luggage is shown in FIG. 1. A perspective view of the components and a cross-sectional view of the locking means 10 are shown in FIGS. 2 and 3, respectively. As shown in FIG. 1, the locking mechanism 10 includes a housing member 14 and a locking pin 16 for engaging an aperture 18 in the inner tube 12 when the locking mechanism 10 is slid into a cavity 20 of the inner tube 12. The housing member 14 is provided with a slot opening 22 at the top surface adapted for the mounting of a vertical sliding block 24. The vertical sliding block 24 is equipped with an aperture 26 at or near the top for connecting to a cable 28, and inclined slot opening 30 at the center portion of the sliding block 24, and a hook 32 at the distal end of the vertical sliding block 24. For connecting to the inclined slot opening 30 of the vertical sliding block 24, a horizontal sliding pin 34 is also provided. The horizontal sliding pin 34 has a slot opening 36 and an aperture 38 through the slot opening 36. The aperture 38 is provided for accepting a mounting pin 40 therethrough. To allow the operation of the vertical sliding block 24, a spring device 42 is provided at the bottom hook 32 of the vertical sliding block 24. The bottom end of the spring 42 is connected to a mounting site 44 provided at the bottom surface of the cavity 20 in the housing member 14.
A cross-sectional view of the locking mechanism is shown in FIG. 3 which can be used to illustrate the operation of the mechanism. The locking mechanism 10 can be first assembled together by installing the vertical sliding block 24 into the vertical sliding slot, or the inner tube cavity 20 through a top opening 22 in the housing members 46, 14. The horizontal sliding pin 34 is then inserted from the front opening 20 onto the vertical sliding block 24 with the slot opening 36 riding on the body of the vertical sliding block 24 and the mounting aperture 38 aligned with the slot opening 30. A special tool must be used for the installation of the mounting pin 40 into the aperture 38 on the horizontal pin 34 and through the slot opening 30 of the vertical sliding pin 24. It is a time and labor consuming process. The spring device 42 is then mounted through the opening 20 onto the hook 32 at one end and onto the mounting site 44 at the other end.
The locking mechanism 10 can be operated in the following manner. When the vertical sliding block 24 moves in a vertical motion in the vertical slot opening 20, the slot opening 30 on the vertical sliding block 24 interacts with the mounting pin 30 and causing a horizontal movement of the horizontal sliding pin 16 in the horizontal slot opening 18. The function of the spring device 42 is to pull the vertical sliding block 24 downwardly such that the tip of the horizontal sliding pin 16 protrudes outside the horizontal slot opening 18 for a locking action with the inner tube 12 through aperture 18. To unlock the inner tube 12 from an outer tube (not shown), the cable 28 is pulled up to cause the upward movement of the vertical sliding block 24 and the retraction of the horizontal sliding pin 16 back into the horizontal slot opening 18 thus disengaging the inner tube from the outer tube.
The locking mechanism 10 while effective in performing its function, requires excessive effort in the assembly of the mechanism. Furthermore, a special tool must be used to mount the horizontal sliding pin onto the vertical sliding block. The assembling process is time consuming and not suitable for a mass production operation.
It is therefore an object of the present invention to provide a locking mechanism for use in a pull-handle assembly that does not have the drawbacks or shortcomings of conventional locking mechanisms.
It is another object of the present invention to provide a locking mechanism for a pull-handle assembly that can be easily assembled by hand without the use of special tools.
It is a further object of the present invention to provide a locking mechanism for a retractable pull-handle system by utilizing a vertical sliding member and a horizontal sliding member for converting a vertical motion to a horizontal motion.
It is another further object of the present invention to provide a locking mechanism for a retractable pull-handle system which utilizes a vertical sliding member equipped with inclined surfaces for engaging similarly inclined surfaces on a horizontal sliding member such that a locking pin can be engaged or disengaged between an inner tube and an outer tube.